US3775073A
Expired / Lapsed
US
⏱️ 0.0 years remaining
In situ gasification of coal by gas fracturing
Assignee: Cities Service Oil Co
•
Filing: 1971-08-27
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Granted: 1973-11-27
•
Expires: 1991-08-27
Abstract
Abstract Two or more wells are drilled into a coal seam. The wells are completed so as to isolate all other strata from the coal seam and a radially extended horizontal fracture is directed by introduction of a first combustion supporting gas under hydraulic pressure so as to connect the wells communitively. A horizontally and vertically directed fracture network is formed within the coal system by ignition of the first combustion supporting gas. A second combustion supporting gas is subsequently injected through at least one well to form a combustion front which may be propagated through the fracture network to produce combustible gases and coal tar liquids.
Inventors
- 👤 V Rhoades
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:22
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B43/24; E21B43/243; E21B43/247; Y; Y10; Y10S; Y10S48/00; Y10S48/06
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
24 words
The process of claim 1 in which: a. the first combustion supporting gas is oxygen; and b. the second combustion supporting gas is air.
Claim 2
Dependent Claim
17 words
The process of claim 2 in which the radially extended horizontal fracture is induced by hydraulic fracturing.
Claim 3
Dependent Claim
34 words
The process of claim 1 further comprising the simultaneous injection of water with the combustion supporting gas so that a water-gas shift reaction is provided to increase the calorific content of the produced gas.
Claim 4
Dependent Claim
53 words
The process of claim 1 further comprising introducing a combustion supporting gas into at least one production well subsequent to the injection of the second combustion supporting gas into the ignited wells to cause a reverse combustion and flow of injected gas, produced gas, and coal tar liquids to the previously ignited wells.
References Cited (Backward Citations)
US1913395A
Cited
US3032102A
Cited
US3167117A
Cited
US3292699A
Cited
US3497335A
Cited
US3628929A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |